The present invention relates to a magazine for replaceable tools used in an automatic machine tool.
The present invention further relates to a tool indexing method for positioning a tool mounted in the magazine into a predetermined position conveying the tool into the front of a machine tool.
Recently, flexible machining system (FMS) has been developed in which a number of juxtaposed machine tools with an automatic tool changing apparatus and other associated apparatus are totally controlled by a computer. In these systems it is necessary to replace tools used in those machine tools when they have been damaged or exhausted, or when an object to be worked is changed, thereby requiring new tools.
Conventionally, a tool is replaced by various methods. These methods include:
(a) Stopping of the machine tool to manually replace a tool.
(b) Using replaceable type tool magazine whereby both a tool together with its tool magazine are replaced by another tool and tool magazine.
(c) Changing a tool between tool magazine mounted on a machine tool and separately provided tool magazine.
The method (a) has the disadvantage that the availability of the machine tool is reduced because of the necessity to stop the machine for tool replacement. It is also disadvantageous in that it is impossible to have the system operate unattended because of the necessity for manual intervention during tool changing. Generally, the machine operates using both tools commonly used for various operations and tools used exclusively for particular operations. Therefore, the method (b) is disadvantageous in that, when these tools are received in one tool magazine, it is necessary to have the commonly used tools in every tool magazine thus making this method uneconomical because of an increase in numbers of tools. Further, it is necessary to provide various means (such as means for conveying the magazine and loading it into the machine tool, means for positioning, means for cramping, etc.), in addition to an ordinary tool changing apparatus, resulting in an increase in the cost of the machine and in the requirement for greater space. The method (c) is also disadvantageous in that it requires various means such as means for conveying and indexing the submagazine and means for loading a tool into the tool magazine mounted on the machine tool, resulting in increased cost and in the requirement for greater space, as with the case of method (b).